This invention relates to an electrically conductive connector for electrical conductors.
In commonly assigned U.S. patent application Ser. No. 483,997, filed Apr. 11, 1983, there is disclosed an electrically conductive connector for electrical conductors. The connector comprises a metal sleeve having a closed end and an open end. A solid slug of solder is positioned in the connector adjacent the closed end thereof and a conductor is then inserted. In some embodiments, when sufficient heat is applied to melt the solder, a pressuring means forces the solder between the conductor and the side walls of the connector and, if a stranded conductor is used, between the strands of the conductor. When cooled, the solder solidifies making a solid electrical and physical joint between the conductor and the connector. A preferred pressuring means comprises a piston and a gas-evolving composition positioned between the piston and the closed end of the conductor. On heating, gas is evolved and creates a pressure behind the piston. On continued heating, the solder melts and the pressure of the evolved gas causes the piston to move axially in the connector toward the open end, pressuring the molten solder and forcing it to flow between the conductor and connector. A preferred piston for use in this embodiment is that described in commonly assigned U.S. patent application Ser. No. 604,791, filed Apr. 27, 1984.
In utilizing a connector of the type described in Ser. No. 483,997, it is desirable to use a flux together with the solder. Preferably, the solder is a cored solder containing flux in cavities within the solder slug. Generally the slug of solder used is cylindrical and the flux is located in several cylindrical bores running the length of the solder. It has been found on storage of such a connector for periods of time typical of shelf-life requirements for such a product, that the flux tends to oxidize, absorb moisture, decompose or otherwise to become deactivated. To prevent this, the solder slug is preferably hermetically sealed in the connector to isolate it from the environment. In such an arrangement, it has been found that when heat is applied, the flux activates, giving off gas which creates sufficient pressure to dislodge the conductor being connected. It has also been found that when using the electrical connector with relatively large diameter conductors, e.g., above about 120 square millimeters, an adequate solder bond is not formed. This is particularly true for stranded conductors, as the central strands of the conductor do not form the desired solid soldered connection.
The present invention is directed to an electrical connector which overcomes the problems associated with the prior art devices.